Apparatus for producing transverse offset perforations on web fabric



Nov. 8, 1966 A. FINKE ETAL 3,283,633

APPARATUS FOR PRODUCING TRANSVERSE OFFSET PERFORATIONS ON WEB FABRIC Filed Sept. 14, 1964 g 2a I Z4- J l \l I l l i I L f I 30 l L 25 2/ 23 I 32 Q 30 32 I I J Ir 3 a 0 L 1 1: o ll E93 3 33 s4 s7 W r 5 i l zrir -e 5% WWW United States Patent 3,283,633 APPARATUS FOR PRODUCING TRANSVERSE 0F SET PERFORATIONS 0N WEB FABRIC Arno Finke and Walter Vietmeier, Lengerich, Westphalia,

Germany, assignors to Windmoller & Holscher, a corporation of Germany Filed Sept. 14, 1964, Ser. No. 396,000 Claims priority, application Germany, Sept. 25, 1963,

W 35,315 4 Claims. (Cl. 83-303) This invention relates to an apparatus for producing transverse, offset perforations on web fabric, and more particularly to perforating stations at the tube-forming station of bag-making machines for the production of bags provided with closing flaps. On the known perforating stations of this type the knife set producing the transverse perforations is attached to knife holders which are mounted on a single shaft and rotate with this shaft in unison with the work cycle of the machine.

Practical experience has shown that the known type of perforating stations has a number of disadvantages. For one thing, the length of the tabs or closing flaps cannot be changed by a simple procedure, and for the other, a uniform perforation across the entire width of the web can be obtained only with difficulty, since several knives are required to produce the perforations along a broken line, that is, to obtain offset perforations, and the knives cannot always be attached to their knife holders with the required accuracy, so that different perforation depths will result across the width of the web. This will jeopardize clean separation of the web portions, together with a danger for producing waste and causing shutdowns.

In addition, on the known types of perforating station described above, the adjustment of a different spacing of th perforations in relation to each other for the production of bags of different length is effected by changing the knife circle and simultaneously exchanging the driving gear on the knife shaft against another, whose pitch circle conforms with the desired tearing length. The knife shaft is driven by the forward pull of the web. For these reasons, adjusting to another bag length is relatively complicated and requires above all keeping drive gears of various size in stock.

It is therefore an object of the present invention to eliminate the disadvantages of the known perforating station by providing an apparatus for producing transverse, offset perforations on web fabric, in particular on paper bag-making machines, characterized in that the perforating knives for producing the perforation lines offset in relation to each other in longitudinal direction of the web are attached to the knife holders of separate knife shafts arranged one behind the other in the direction of the web feed, and that each knife shaft and the web are each angularly adjustable in relation to each other in the plane of the respective axis of rotation vertical to the transport direction of the moving web. By mounting the knives on separate knife shafts the knives on each shaft are at least no longer inclined in various directions to the knife shaft. In accordance with this invention any inclined position in one direction resulting from attaching the knives to the knife holders can be equalized by inclining the knife shaft in relation to the web, so that a uniform perforating depth of any knife extending transverse to the longitudinal direction of the web can be attained across its entire length. In addition, a very simplified change in length of the bag flaps is possible by, for example, loosening the driving connection of the shaft with the knife for the central portion of the perforating line, adjusting the shaft toward the other knife shaft accordingly and re-establishing the driving connection. Then, only the knives on the other shaft for those parts of the perforating line in direction of the web feed need be exchanged against other knives conforming with the desired length of the flaps.

A further object of the invention is the provision of a counterpressure roller for each knife shaft, mounted on a shaft whose ends can be jointly and individually adjusted in the machine frame vertically to the plane of the web. The joint adjustability of the ends or journals of the counterpressure rollers permit the removal of the counterpressure rollers from the knife circle, which is required when adjusting the apparatus to another bag length, and the individual adjustability of the counterpressure roller journals permits the above named angular adjustment of the moving web in relation to the respective knife shaft, Where it is a special advantage that the angular position can be changed by means of the counterpressure roller, since the latter is not a part of the drive train. To permit the shifting of the counterpressure roller journals bearing blocks for each counterpressure roller journal can be mounted in guideways of the machine frame and adjusted by means of an adjusting screw, with the two adjusting screws of each counterpressure roller being in individually detachable driving connection with each other by means of a manual- 1y operated adjusting shaft. In addition, the invention permits changing the knife circles in a manner known as such and the knife shafts can be permanently supported in the machine frame and driven by means of a driving connection in unison with the work cycle of the machine and independent of the pulling action of the moving web. Exchanging the drive gears when adjusting the machine to another bag length is therefore no longer required. Only the knife circle need be changed, while the drive gear on each knife shaft always remains the same. The knife shafts can be driven by a single-revolution shaft, that is, a shaft which makes one revolution per bag independent of its length. To fit the various knife circles the counterpressure rollers, as already stated above, can be moved in the machine frame in vertical direction to the web.

In the following description the invention is described in detail on the basis of the attached drawing, which shows one embodiment of the invention.

In the drawings:

FIG. 1 is a diagrammatic side view of the new perforating station;

FIG. 2 is a top plan view in the direction of arrow II in FIG. 1 on a transversely perforated web section, and

FIG. 3 is in its left half a section according to lines A-B of FIG. 1, and in its right half a section according to line C-D of FIG. 1.

In the bag-making machine the perforating station is located between a fixture 1 for attaching a longitudinal adhesive strip and a tube-forming station not shown. By means of a pair of pulling rollers 2, 3 the web 4 is pulled off a supply reel not shown. The path of the web through that portion of the bag-making machine shown in FIG. 1 is drawn in a dot-anddash line. The running direction of web 4 in FIGS. 1 and 2 is shown by arrows.

According to the present invention the toothed knives 10, 11, 12 required to produce the transverse, offset perforations 5 to 9 (FIG. 2) are mounted on two knife shafts 13, 14 located parallel to each other and one behind the other when seen in longitudinal direction of the web. Two knives 10 are used for producing portions 5 and 9 of the perforated line and they are connected with each other in the central part by means of a Web without perforating teeth to prevent that the cutting edges of these two knives are at an angle to each other, two knives 11 are used for making portions 6 and 8, and one knife 12 is used for making portion 7. Knives 10 and 11 are attached to knife holders 15 and knife 12 to knife holders 16, which are rigidly connected with shaft 13 or 14. A single-revolution shaft not shown drives a gear wheel 17 which is in mesh with a gear wheel 18 on knife shaft 13 and with a gear wheel 19 on knife shaft 14. Knife shafts 13, 14 are driven in such a manner that they perform one revolution for each machine cycle. Gear wheels 18, 19, for example, are attached to shafts 13, 14 by means of a detachable clamping connection so that after release of the clamping connection the shafts can be turned for any required adjustment.

The offset between portions or 9 and 7 of the perforate-d line provides the dimension for the flap length of the manufactured bags. This flap length can be changed by adjusting knives 10 and 12 relatively to each other. This adjustment is effected by the already named loosening of, for example, the connection of gear wheel 19 to shaft 14, by turning the shaft for a given distance and by reestablishing the rigid connection between shaft 14 and gear wheel 19. Knives 11 for making portions 6 and 8 of the perforated line must still the exchanged against those providing the length of the desired flap.

Shafts 13, 14 are rotata-bly mounted in the machine frame, but not vertically slidable toward the web, because in this design the distance of the axis of shaft 13 or 14 from the axis of gear wheel 17 remains constant and independent of the length of the bag to be manufactured. If the machine must be set for another bag length, that is, for another spacing of the perforated lines from each other, only the knife circles are changed as required by exchanging the intermediate pieces provided and by resetting the counterpressure rollers 20 and 21 in relation to th new requirements. For this purpose, the shafts 22, 23 of the counterpressure rollers are screwed by means of two screws 24 each to two supports 25 sl-idably located between two guide rails 28, 29 each on walls 26, 27 of the machine frame. Support pieces 25 of shaft 23 are each held by a screw spindle 30 screwed into a threaded hole of the support piece for movement into any desired vertical position. Support pieces 25 of the shaft 22 are displaced by means of screw spindles 31. Screw spindles 30, 31 are rotatably mounted, but axially immovable, in bearings 32, which in turn are attached to frame walls 26, 27. At their nonthreaded end projecting from bearin g 32 screw spindles 30, 31 carry one bevel gear 33 each. Each bevel gear 33 is in mesh with a bevel gear 34 on an adjusting shaft 35 or 36. Adjusting shafts 35, 36 are operated by means of one handwheel 37 each.

Since, as already stated above, it is hardly possible to attach perforating knives 10 and 12 to their knife holders with the required accuracy it is another object of the present invention to provide means for obtaining a uniform perforating depth by proper adjustment of the web in dependence of perforating knives 10 and 12 in such a manner that the counter-pressure rollers 20, 21 are raised or lowered at either end to meet the respective requirements. This one-sided raising or lowering of the counterpressure roller 21 is effected by taking the right-hand bevel gear 34 on the adjusting shaft 36 shown in FIG. 3 out of mesh with bevel gear 33 and by then turning the adjusting shaft 36 by means of handwheel 37 in the desired direction. This will raise or lower the left-hand end of the counterpressure roller 21, as shown in FIG. 3, for an accurate match to the position of perforating knife 12. Matching counter-pressure roller 20 to perforating knife 10 is done in a likewise manner by loosening one bevel gear 34 on adjusting shaft 35, followed by turning this adjusting shaft as required.

Counterpressure rollers 20, 21 are not driven rollers, they are rotated by the motion of the web above. As shown in FIG. 3, right, they rotate freely on their shafts but cannot be shifted in axial direction. The counterpressure rollers are provided with a rubber coating to absorb the points of the perforating knives after perforating the web.

The present invention is not restricted to the embodiment shown. For example, the two knives 10 can also be placed into a concentrically continuous slot of their knife holder and need not be connected to each other in such a case, because their mutual alignment is here assured by their abutment against the straight bottom surface of their common holding slot. If there is no such common holding slot, nor a connection of these two knives for the outer portions of the perforated line included in the design, the two knives must be mounted on two separate knife shafts together with the pertinent counter rollers.

We claim:

1. An apparatus for producing transverse offset perforations on a web material in particular for bag-making machine's comprising a plurality of perforating knives, for those portions of the perforated lines offset in relation to each other in the longitudinal direction of the web, mounted on knife holders mounted on at least two separate parallel rotating knife shafts, said knife shafts being fixedly mounted spaced from each other in the direction of the web feed, each said knife shaft and the material web being angularly adjustable in relation to each other in a plane perpendicular to the transport direction of the moving web which includes the axis of rotation of said knife shaft so that the plurality of perforating knives can be adjusted to compensate for any oblique positioning with respect to themselves and each other.

2. An apparatus according to claim 1 in which the angular adjustment is achieved by a counterpressure roller provided for each knife shaft, said counterpressure roller being supported on a shaft whose ends are jointly and individually adjustable in said plane perpendicular to the transport direction of the moving web.

3. An apparatus according to claim 2 in which the ends of said counterpressure roller shafts are adjustably supported in guideways on a machine frame by means of separate screw spindles, and said screw spindles of each counterpressure roller being individually and detachably in driving connection with a manually operated adjusting shaft.

4. An apparatus for producing transverse, offset perforations on a web, in particular for bag-making machines comp-rising a first toothed perforating knife for forming a portion of the perforated lines offset in relation to each other in the running direction of the web, a plurality of additional toothed perforating knives for forming additional offset perforated portions and those portions of the perforated lines interconnecting said offset lines, said knives being mounted on separate knife holders mounted on separate parallel, rotating knife shafts, said knife shafts being fixedly mounted located one behind the other in the direction of the web feed, each knife shaft and the web being angularly adjustable in relation to each other in a plane perpendicular to the transport direction of the moving web which includes the axis of rotation of said knife shaft.

References Cited by the Examiner UNITED STATES PATENTS Re. 16,384 7/1926 McCrohan et al. 83346 856,560 6/1907 Walker 83-344 940,515 11/ 1909 Claussen 9333 1,487,662 4/1924 Langston 8349 2,285,228 6/ 1942 Potdevin 93-33 2,100,519 11/ 1937 Robinson 93-33 2,285,228 6/1942 Potdevin 9333 2,307,142 1/ 1943 Lee 93-33 WILLIAM W. DYER, JR., Primary Examiner.

L. B. TAYLOR, Assistant Examiner. 

1. AN APPARATUS FOR PRODUCING TRANSVERSE OFFSET PERFORATIONS ON A WEB MATERIAL IN PARTICULAR FOR BAG-MAKING MACHINES COMPRISING A PLURALITY OF PERFORATING KNIVES FOR THOSE PORTIONS OF THE PERFORATED LINES OFFSET IN RELATION TO EACH OTHER IN THE LONGITUDINAL DIRECTION OF THE WEB, MOUNTED ON KNIFE HOLDERS MOUNTED ON AT LEAST TWO SEPARATE PARALLEL ROTATING KNIFE SHAFTS, SAFE KNIFE SHAFTS BEING FIXEDLY MOUNTED SPACED FROM EACH OTHER IN THE DIRECTION OF THE WEB FEED, EACH SAID KNIFE SHAFT AND THE MATERIAL WEB BEING ANGULARLY ADJUSTABLE IN RELATION TO EACH OTHER IN A PLANE PERPENDICULAR TO THE TRANSMPORT DIRECTION OF THE MOVING WEB WHICH INCLUDES THE AXIS OF ROTATION OF SAID KNIFE ADJUSTED TO COMPENSATE FOR ANY OBLIQUE POSITIONING WITH BE ADJUSTED TO COMPENSATE FOR ANY OBLIQUE POSITIONING WITH RESPECT TO THEMSELVES AND EACH OTHER. 